ABSTRACT The goal of this proposed R21 grant is to test the feasibility of a theoretically informed, school-based intervention for LGBT adolescents (Proud & Empowered; P&E). LGBT adolescents experience disparities in behavioral health outcomes compared to their heterosexual peers. For example, LGBT adolescents are 3 to 4 times more likely to meet criteria for an internalizing disorder and 2 to 5 times more likely to meet criteria for externalizing disorders than their heterosexual counterparts. This is commonly attributed to minority stressors, including victimization in schools, that is associated with poor school climate. Our intervention seeks to address these disparate behavioral health problems through use of a novel multi-level school-based prevention intervention. Our goal will be achieved by completing two specific aims: 1) Assess the feasibility (i.e., recruitment, enrollment, fidelity of service delivery, satisfaction, safety, and retention) and participant-level efficacy of the intervention in a delayed intervention RCT with four schools. 2) Obtain preliminary estimates of school-wide intervention effects on (a) reporting of minority stress and behavioral health outcomes among all LGBT students and (b) changing climate (norms, attitudes, beliefs, bullying behaviors toward LGBT youth) among all students. We expect that (H1) LGBT students in schools where the P&E intervention is delivered will report fewer minority stress experiences and fewer behavioral health symptoms as compared to LGBT students in control schools, even if they did not participate in the 10-week P&E intervention themselves; and (H2) students in schools where the P&E intervention is delivered will report improvements in school climate toward LGBT students as compared to students in control schools. This innovative R21 application brings together a team of nationally recognized minority stress and prevention science experts and responds to a nationally established public health need for research from the National Academy of Medicine, the National Institutes of Health, and the National Gay and Lesbian Task Force.